Bug: Repeated fetching and deletion causes an error.

[PikaByter]

Hello, I encountered a bug while testing modctl.
After pulling and then removing an image, if I pull and remove the same image again, the removal fails and the operation is not idempotent.

root@server25:~/myth/bin# ./modctl rm igeniestudio-harbor-yyyy.xxxx.com/ml-xxxx/qwen2:0.5B
Error: failed to delete manifest 0.5B: filesystem: Path not found: /docker/registry/v2/repositories/igeniestudio-harbor-yyyy.xxxx.com/ml-xxxx/qwen2/_manifests/tags/0.5B

Reproduction steps

modctl pull <image>
modctl rm <image>
modctl pull <image>
modctl rm <image>